Could this forearm belong to someone who is working their local aerobic endurance? Keep reading and find out...

Some define it as the ability to:

- Recover from one try to a route to the next, and also at resting points during a climb
- Climb long, easy-medium intensity sections without getting overly pumped
- Climb a long route, climb a lot of routes or try the same route several times during one day.

The routes we tend to associate with this quality lack a very hard crux and are usually long. For example, they are 25-30+m long, have 60-80 moves or take more than 20 minutes to ascend even when we know the moves.

Local Aerobic Endurance and Energy Systems

Attending to its main metabolic source of energy, long duration and low intensity, some authors place it within aerobic endurance, that relies on the oxidative system. Others go a bit further and point the low volume of muscle that is involved (less than 1/6-1/7 of the total). So they use the -more accurate- term local aerobic endurance or local aerobic-anaerobic endurance.

We still have to acknowledge one fact: it is possible to deduce what the main energy source is for a given section of a climb, attending to several factors (hold depth, overhang angle, speed, duration, etc.). But sport climbing as an aggregate is an intermittent sport; there is movement and there are stops, there are easy and hard segments, there is holding and releasing... this makes for an assortment of metabolic and physiologic characteristics. Among them, anaerobic alactic and aerobic metabolism (Bertucci et col., 2007), are the most important.

Chart adapted from Guidi (1999)

A note on terminology
Why does the 'local' qualifier make the term more accurate? Because it reminds us that the criteria that are useful when dealing with other sports of similar
duration to indoor competitive climbing (like running 1500 or 3000m) or
onsighting a rock route (like running 10k or swimming 1500m) are not applicable to sport climbing.

The reason is that those sports involve a big (more than 1/6 of the total) volume of muscle, and the load they have to displace represents a low percent of the maximum strength of the implicated muscles. One consequence is the need for an increased blood flow. Therefore, cardiovascular endurance, also known as aerobic power (measured through maximal oxygen uptake -VO2max-) and aerobic capacity (performance at or close to lactate threshold) are more relevant than the local or muscular factors.

Physiological Demands of Sport Climbing
In fact, during progressive climbing sets (steepness) in a treadwall (Schöffl et col., 2006) no point was found after which lactate accumulated exponentially as it happens in other sports: the increase was merely linear. These authors concluded that blood lactate can show the evolution of a climber in a given route, but we can't talk about a 'lactate threshold' per se. It can be argued that these results may vary if reducing hold size was used as the way to increase difficulty instead of running the treadwall faster or steeper... anyway: given the small absolute amounts of lactate measured and the particular characteristics of our fatigue (that can't be explained by acidosis alone), it could be even more fitting to talk about 'local fatigue threshold' (term coined in honor to the interesting conversations with my colleague P. Bergua) than about 'lactate threshold'.

So, even if it has been shown that a 3 to 5 minute climb achieves a considerable fraction of the VO2max obtained in a treadmill (70-85%; Billat et col., 1995; Lehner, 2000; De Geus, 2006), and this has led many authors to suggest that climbing depends a lot on aerobic metabolism (Billat et col., 1995; Booth et col., 1999; Watts and Drobish, 1998), this in no way means that climbing is an 'Aerobic Power' sport, like the rhythmic, uniform and global ones mentioned above.

There is even data that shows that climbers who train their cardiovascular endurance through unspecific aerobic endurance exercises (running, cycling...) take less time to recover their heart rate between climbing sets (Schöffl et col., 2006); and we can go as far as suggesting a method for aerobic power development specific of climbing (later in the series we will see how and for whom this would make sense). Nonetheless this hasn't been enough to show that this is a key performance factor in climbing (Billat et col., 1995; Watts et col., 2004; España-Romero et col., 2009). Instead, what has been proposed as a key quality is the local or peripheral factor, specifically the strength-endurance to intermittent isometric contractions of the finger flexors (Billat et col., 1995; Watts, 2004; Schöffl et col., 2006).

Summing up: Climbing is an intermittent sport that involves a lot of isometric action of small muscles that have to bear most of the body's mass, and these realizations are capital for understanding fatigue and developing training methods accordingly.

We can't use blood lactate, heart rate or VO2max to evaluate or choose a training method, because these parameters have not been shown to be representative of intensity in climbing (Koestermeyer, 2000; Michailov 2002; Schöffl et col. 2006; Burnik and Jereb, 2007). Then, what factor do we use to train not only local aerobic endurance, but also other forms of endurance?

Intensity will be a function of what fractionof our maximum strength we need to grab a hold (given by its depth, shape, texture...) along with grip duration (a function of foot- and handhold distribution, clipping points...) in a given route (steepness, etc.) (López-Rivera, 2014).

The logical conclusion is that we need to choose holds of a size that allows us to maintain the activity and sensations associated to local aerobic endurance for the required time on a climbing surface (with its own overhang, hold distribution, etc.).

Planning for Local Aerobic Endurance: BasesWe usually hear about high volume and low intensity training, with many sets of easy, homogeneous climbing and short rests, or climbing many rock routes in a day, etc.

We are not going to discuss here some popular methods (like 4x4's) or other methods put forward by different authors. We won't learn how to train local aerobic endurance in general, because I believe it to be too simplistic.

What we are going to do is reviewing what I think are the 3 specific goals or the 3 aspects that determine the training of this quality.

Why?

Because in my opinion this will allow us to define it more accurately, allowing us to guide our work more effectively. Analyzing what effects we want to achieve in each case (what route we want to climb, our level, modality we practice, etc.) will make it easier to choose a method for each mesocycle and macrocycle.

Training your Local Aerobic Endurance: Goals

GOAL #1: Make our forearms capable of completing a climb without getting 'depleted'.

In other words, enhancing CAPACITY, also known among climbers as ARC (aerobic energy restoration and capillarity)

GOAL #2: To be able to conserve our strength through long, low- to mid-intensity sections.

To put it another way: reducing fatigue and pumped forearms on easier parts, no matter their length.
We can refer to this goal as STEADY-STATE (negotiating moderate intensity-medium duration sections), or EFFICIENCY or economy of movement (okay, we are venturing into the realm of technique, but who says these things are unrelated?)

This goals' importance (and the first one's, not only because it helps developing #2) is supported by the suggestion that climbing time to exhaustion (España-Romero et col., 2009) and economy (España-Romero et col., 2009 and 2011; Bertuzzi et col., 2007; Baláš et col., 2013) -defined as the least energy expenditure per move at a given intensity- are key performance factors.

GOAL #3: ABILITY TO RECOVER

This quality is a requirement of the heterogeneous and intermittent nature of rock climbing, and there are several reasons why this can determine performance:

- It takes less time to recover from hard moves, not only at good rests, but also while moving, when we shake our free arm, or even while chalking up! Our chances will improve when facing the crux because of the fast phosphagen repletion (an energy substrate for high intensity efforts), optimal oxygenation and recycling-elimination of fatigue-related metabolites. We will also be able to give the same route more tries during one day.

At the metabolic level it could be described as a combination of the aerobic and anaerobic pathways. According to the terminology that is popular among climbers, these goal fits somewhere between endurance and power-endurance.

General guidelines for goal-based periodization according to level and training phase

LOWER LEVELS: Earlier training stages and Beginners
At this stage we will focus on Goal #1, because when we start training or climbing we tend to lack enough capacity (Bertuzzi et col., 2007), probable due to poor technique and low finger strength. Some telling signs of insufficient capacity are getting exhausted before sorting all the moves of a route in one try, having limited 'energy' to climb several routes even if they are easy or familiar and getting pumped too soon.

INTERMEDIATE LEVELS/medium training stages
Once the previous stage is taken care of, it is possible to begin training for Goal #2. Here we will develop our Efficiency, meaning the ability to climb at low-mid intensity without getting too pumped, or feeling pain or stiffness in our forearms.

HIGHER LEVELS
Advanced climbers, once they have addressed the previous goals both through their sport career and during the season, can proceed to methods aimed to achieving Goal #3, being able to recover their forearms in record time, while climbing and also from route to route.

Eva López on Géminis, 8b+. Rodellar. Photo: Dafnis Fernández

Regarding the way these methods are arranged in the training plan, the first two goals will build the foundation to develop the third more effectively. The latter (or the two first for lower-intermediate level climbers), combined with that other quality that we know as 'power-endurance' ('resistànce' in French), will translate into improved performance when it comes to endurance.

This said, I need to remind everyone that we can't ignore other qualities: boulder, finger strength, etc. We also have to choose our goals and associated methods for each of them.

The description of the different training methods that are indicated for the fulfillment of each Goal will be the topic of the next entries.

de Geus, B., O’Driscoll, S. V., and Meeusen, R. (2006). Influence of climbing style on physiological responses during indoor rock climbing on routes with the same difficulty. European journal of applied physiology, 98(5), 489-496.